The study proposes to expand on findings made among 94 children and adolescents having "chemical" diabetes (n equals 49), insulin-dependent diabetes (n equals 7), or diabetes with cystic fibrosis (n equals 38), and to extend the studies to newly diagnosed "chemical" diabetics and to a clinic population of 125 insulin-dependent youth. (1) The finding of hyperglucogonemia (as well as hyperinsulinema and modest hyperglycemia) in a significant number of "chemical" diabetics and in some diabetics with cystic fibrosis, similar to levels seen in insulin-dependent diabetics, together with recent report that glucagon stimulates acute phase proteins in animals, is the basis for examining levels of fibrinogen, alpha-1 antitrypsin, haptoglobin, albumin and globulins, Factor VIII ywf, platelet and red cell aggregability - factors known to be altered in adult diabetics and possibly etiologic in diabetic microangiopathy. (2) The finding that abnormal amounts of hemoglobin adhere to red cell membrane proteins in diabetic youth will be examined in relation to red cell deformability. Retinal studies (indirect ophthalmoscopy, color retinal photography, fluorescein angiography will be done on youth able to co-operate, at two intervals 18 months apart, to determine if there is a correlation between capillary angiopathy, acute phase proteins, and hypercoagulability; and to provide baseline data in a young population for future possibilities of therapeutic intervention. (3) The finding that youth with cystic fibrosis fail to release Phase 1 insulin independent of their glucose will be studied in respect to plasma levels of Gastric Inhibitory Polypeptide, a gastro-intestinal hormone which stimulates early insulin release.